+++++++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: "Elecraft" Subject: RE: [Elecraft] K2 2390 Lives! But got a question or two.... Date: Mon, 7 Jan 2002 18:49:14 -0800 Rick wrote: >All seems to work well "BUT" I got a > question or two. While measuring power output and tweaking for maximum > output I used a Daiwa CN-101L SWR & Power meter and the internal power > meter. I also used a 50 watts MFJ versaload dummy load (Like the cantenna > dummy load) I have the following statistics with full power output on each > band: > > Frequency Daiwa CN-101L Internal Power meter > 3.750 10 watts 12.1 watts > 7.100 11 watts 13.2 watts > 10.100 10 watts 12.1 watts > 14.100 11 watts 12.5 watts > 18.100 11 watts 12.1 watts > 21.100 11 watts 12.6 watts > 24.900 10.5 watts 13.2 watts > 28.200 9 watts 12.3 watts > > I was hoping for the full 15 watts... I > note that some of the bands hit 2.50 amps which sets off the high current. > Usually I get high current flashing but not consistently. The K2 is rated for only 10 watts output. The 15 watts is available on SOME bands if you have a full 13.8 volts on the supply line. That's the margin Elecraft designed in to be sure every K2 meets the spec of at least 10 watts out. So you seem to be a bit low on 28.2, but most power meters are doing well to be accurate within 20%, so your readings are not surprising. Ten meters us usually the band with the lowest power output. You WILL get a "high current" with the limit set to 2.5 amps. If you want to open 'er up all the way on all bands, a typical K2 may draw more than 3 amps on some bands. Ron AC7AC K2 # 1289 ++++++++++++++++ Date: Mon, 07 Jan 2002 19:19:16 -0800 From: Phil Wheeler Organization: Outstanding To: Rick Tilton CC: Elecraft Subject: Re: [Elecraft] K2 2390 Lives! But got a question or two.... There are measurements from an early build (not mine) at this url: http://www.qsl.net/kw1nd/k2.htm 73, Phil Rick Tilton wrote: > > OK.. Success! K2 #2390 Lives! All seems to work well "BUT" I got a > question or two. While measuring power output and tweaking for maximum > output I used a Daiwa CN-101L SWR & Power meter and the internal power > meter. I also used a 50 watts MFJ versaload dummy load (Like the cantenna > dummy load) I have the following statistics with full power output on each > band: --- snip --- +++++++++++++++++++ Date: Mon, 07 Jan 2002 23:14:46 -0500 To: "Rick Tilton" From: Dave Gingrich K9DC Subject: Re: [Elecraft] K2 2390 Lives! But got a question or two.... Cc: "Elecraft" At 21:23 1/7/2002 -0500, Rick Tilton wrote: >I was hoping for the full 15 watts but HEY! I feel pretty good. Anyway.. I >note that some of the bands hit 2.50 amps which sets off the high current. As others have mentioned... 10 watts is the rating. 150% of rated is a lot to expect, and you won't probably get there on all bands. >Usually I get high current flashing but not consistently. If I leave it for >several seconds it may clear up and not flash high current at all when >pressing the tune button. It is not like it is always there but it does >come on sometimes when I hit the tune button initially. Should I be >concerned? It appears to be normal but I would like to have a second >opinion. Sounds pretty normal to me. Although you will need to raise the current limit up to 3.0 or 3.2. Keep in mind that the radio will draw less current if the input voltage is higher, due to the ALC action. I feed mine with about 14.3 out of the PS which results in 13.9 indicated on the display (difference being the drop across the input diode). Ideal for keeping the internal battery charged. ================================================ Dave Gingrich, K9DC - Indianapolis, Indiana USA +++++++++++++++++ Date: Tue, 08 Jan 2002 06:43:36 -0500 To: "Elecraft" From: Charles Greene Subject: RE: [Elecraft] K2 2390 Lives! But got a question or two.... Just for info, I have a Daiwa CN-101L and I get similar readings. The Daiwa appears to be about 10% low compared to a Autec WM1 SWR/Power meter, the internal power meter in the Ten Tec Omni-VI, and the power meter in an IFR service monitor. So you should believe the K2 power readings. At 06:49 PM 1/7/2002 -0800, Ron D' Eau Claire wrote: >Rick wrote: > > >All seems to work well "BUT" I got a > > question or two. While measuring power output and tweaking for maximum > > output I used a Daiwa CN-101L SWR & Power meter and the internal power > > meter. I also used a 50 watts MFJ versaload dummy load (Like the cantenna > > dummy load) I have the following statistics with full power output on each > > band: > > > > Frequency Daiwa CN-101L Internal Power meter > > 3.750 10 watts 12.1 watts -- snip -- 73, Chas, W1CG ++++++++++++++ Reply-To: From: "Ron D' Eau Claire" To: , Subject: RE: [Elecraft] voltage input dropping pwr out Date: Tue, 9 Apr 2002 13:27:24 -0700 > I can't seem to get the right amount of power out for each band, and my > car battery will not give enough current for power out to be higher than > 0.2W, same for the power supply I have (which I might be able to fix) > and my batteries. > > I only seemed to be able to get out 15.8W at 13.4V input. > > I am using a power cable that is used on CPUs. How can I do better? > > Daniel I'll assume that you are talking about a K2 and not a K1 since you mention 15 watts. Unless your car battery is long past dead, it'll give you plenty of current. The question is "what is the voltage at the K2?". With the K2 on, momentarily press DISPLAY and note your voltage. It should be over 13 volts in receive, and something over 12 volts on transmit at the full output of the K2. >From what you say, I suspect that it is lower than that. So you get out your voltmeter and check what you have at the cable side of the connector going to the back of the K2. Note that it will be about 0.6 vdc or so more than the K2 displays because of the drop in the reverse-protection diode in the K2. If that's good, then your connector is making bad contact. It it's low there go to the point where your power cable connects and check there and keep working back to the battery. Somewhere you will see the voltage drop under load disappear, and then you will know where the high-resistance connection is. Note that the K2 is RATED at 10 Watts output! SOME bands typically provide more - something as high as 15 watts on some bands is not uncommon, but the rated output of the K2 is 10 watts and that's just about all you will get on some bands (typically 10 meters is the band where the output is lowest). Also if you are using SSB, note that Elecraft recommends not going above 10 watts output on ANY band, regardless of who much output the K2 can make. That's because the IMD suffers when the finals are driven above their design specs. Ron AC7AC K2 # 1289 +++++++++++++++++ Date: Sun, 26 May 2002 03:05:18 -0400 (EDT) From: kc4kgu at ENTERZONE.NET To: "Richard M. Cash, W4UGM" Cc: "Elecraft List (Mail)" Subject: Re: [Elecraft] K2 Problems On Sat, 25 May 2002, Richard M. Cash, W4UGM wrote: > I just finished my K2, #2639 and am having some problems. Most > everything seems to work OK except that the output power decreases as > the bands go higher. I get only about 6w on ten meters into a dummy > load. Also, the ALC indicator does not work on 10. I've checked the > components and re-soldered the connections several times. Any help > would be appreciated. I have the basic K2 with the SSB adapter > installed. 73 Richard W4UGM Richard, It is common to have less power out on 10m than at 75m or 160m. I would say that you should be able to achieve more than 6w though, once you have the rig properly aligned. I just put K2 #2490 into "QRP" configuration and I see the following power levels with the RF power knob fully clockwise: 160m 14w 80m 16w 40m 16w 30m 14w 20m 13w 17m 16w 15m 13w 12m 13w 10m 10w If you will notice, power out goes lower as we get higher in frequency. I get 10w on 10m even if I set the "Po28" setting to 15w. As for your ALC not working on 10m, note that the function of the ALC is to reduce power output to protect the final power transistors and/or keep absolute peak power out reasonably close to what you have requested with the RF power setting. Since your K2 is not making "rated power" yet on 10m, you will see no ALC action because it is not having to reduce drive to protect the transistors, etc. One way to check this is to turn your RF power knob fully counter-clockwise (request 0.1w power) and THEN talk into your microphone. With the MH2 (a HOT microphone by comparison to many), SSBA=3 and SSBC=4-1, requesting 15w on 10m, I can whistle VERY loudly into the microphone and not get any ALC action at all. If I turn requested power to something _LOWER_ than what K2 #2490 is capable of delivering, say 5w for example, I will get ALC action, although it is VERY little, as in one light. In aligning your K2, keep in mind that there will often be more than one position that will prodoce a "peak" in power output. After two or three tries, you'll most likely find the one that will produce closer to 10w peak if not more than 10w. Also remember that the band-pass and low-pass filters are shared between the following bands: Band-Pass --------- 80/160 40 20/30 15/17 10/12 Low-pass -------- 160 80 40 20/30 15/17 10/12 There will be come compromise when tuning. I hope this helps. 73 de John - KC4KGU Proud owner of the first production K2/100 on the air! K2/100 #2490 ++++++++++++++++ From: BobDobson at aol.com Date: Sun, 26 May 2002 08:34:18 EDT Subject: Fwd: [Elecraft] K2 Problems To: elecraft at mailman.qth.net There is a modification that addresses this issue. Try elevating T2 about 1/8" above the board. I did this when I built my K2 and I get at least 15W out on all bands. 73, Bob WA4FOM ++++++++++++++++ Date: Sun, 26 May 2002 11:44:31 -0500 To: Kevin Cozens , elecraft at mailman.qth.net From: Tom Hammond =?iso-8859-1?Q?N=D8SS?= Subject: Re: Fwd: [Elecraft] K2 Problems Kevin: >>There is a modification that addresses this issue. Try >>elevating T2 about 1/8" above the board. I did this >>when I built my K2 and I get at least 15W out on all >>bands. > >You get 15W out on ALL bands?? What is your secret, Bob? I raised T2 above >the board by the thickness of some perf board material (approx. 1/16"). >This increased my power out on 10m from about 9.5w to about 10.5w. Sometimes all it takes is careful alignment. Try re-peaking (for max. output) on each band, using about 1W output. 73, Tom Hammond N0SS +++++++++++++++++++ From: "Rod N0RC" To: "Elecraft-list" Date: Sun, 26 May 2002 11:38:13 -0600 Subject: [Elecraft] K2 Power tweaks for the upper bands Folks, Here a few tricks I learned from Gary Surrency: 1) Expand and/or compress the toroid windings in the PA LPF for 10&12m, L21 & L22. The effect is small usually less than 1 watt. But, it does get the LPF optimized. 2) Interleave the windings of T4. This can be a "biggie". I raised Pout of my K2 by almost 2W just by doing this. 3) As others have noted, raise T2 about 1/8 inch above the board. Doing all of these mods got my K2 up to about 12-13W on 10 and 12m. All others bands are in excess of 15W. (Of course I'd never run that much power ;-) 73, Rod N0RC ++++++++++++++++++++ Reply-To: "Ron D'Eau Claire" From: "Ron D'Eau Claire" To: Subject: Re: [Elecraft] Inconsistant drive with SSB Date: Tue, 28 May 2002 20:40:41 -0700 > I have noticed something for a while with my K2. I can get 10w+ on all > bands in CW mode. When I switch to SSB, the amount of tx audio required > varies GREATLY from band to band to achieve 10w peak. > > I will be doing some experiments tonight to try to determine a cause. Has > anyone else noticed this with their K2+KSB2? > > 73 de John - KC4KGU > K2 #2490 Yes. That is NORMAL behavior. The total gain of the transmitter r-f amplifier chain varies widely from 160 or 80 meters to 10 meters. Usually the gain is lowest at 10 meters, which is why that band usually shows the lowest "maximum" r-f output at "full power" setting. The ALC in the K2 works by adjusting the audio level to produce the requested power output, so it will require different levels of audio depending upon the band. You can see this by watching the ALC function (press & hold RF/ALC) on the bargraph. On bands where the r-f gain is highest through the transmitter circuits, you will have maximum ALC action. 40 meters will usually show two or even three bars of ALC on voice peaks. 10 meters, on the other hand, often barely flashes one bar. You should be able to get 10 watts, peak, on any band. The bargraph shows "peak" r-f output on SSB. Keep in mind that 10 watts peak is all the power Elecraft recommends to avoid excessive IMD on your signal even though you may be able to get a few more watts out on some bands. . Ron AC7AC K2 # 1289 ++++++++++++++++ Reply-To: "Ron D'Eau Claire" From: "Ron D'Eau Claire" To: Subject: Re: [Elecraft] New K2 with 5W check problem Date: Sun, 2 Jun 2002 10:28:56 -0700 > A couple of times at 18.200 and also 21.250 MHz when going into Tune, I got > a high current warning and 10+ watts out. Stopped the tune, pushed it again > and it returned to normal. > > I did the transmitter alignment for all bands prior to measuring the above. > > Where do I go from here? Need some ideas because Gary must be out > of town since Friday. TIA Jeff, K6TFZ Did you spin the trimmer caps around a bunch of times to "seat" the contacts before adjusting them? Many of those trimmers come from the factory not yet making good electrical contact inside, which makes them work poorly or not at all. They aren't defective. They just need to have their contacts "seated" by turning them around several times before trying to adjust the filters. Two common symptoms of not seating the caps are no power output (often on 20) and erratic power output levels. Ron AC7AC K2 # 1289 +++++++++++++++++++ From: K6TFZ at aol.com Date: Sun, 2 Jun 2002 15:57:18 EDT Subject: Re: [Elecraft] New K2 with 5W problem Now Almost Fixed To: elecraft at mailman.qth.net, gary at elecraft.com Ron, AC7AC instantly fixed the low or no output on the two bands (20 and 17 meters). Spinning the caps did the trick. For the other who asked: Yes, I am loading into a dummy load. Another person has a similar problem with Tune going into high current for no apparent reason, turning back to rx, Tuning again and appears normal. Do others have that same problem? Now all I have to worry about is the somewhat high current of 2.46 amps only on 40 meters with only 5 watts out. Thanks for the fast help. It's terrific!!! Jeff, K6TFZ +++++++++++++++++++ Reply-To: "Don Wilhelm" From: "Don Wilhelm" To: "g3pjt" , Subject: Re: [Elecraft] Power output Date: Mon, 10 Jun 2002 22:24:50 -0400 Bob, You should have at least 10 watts of power on 10 meters (assuming you are feeding a 50 ohm non-reactive load - like a good dummy load or a properly tuned antenna). The low pass filters as well as T4 can reduce your power output. Check T4 (and T3 too) for the correct number of turns. Gary Surrency has said that T4 works much better if the turns are interlaced rather than just overlaid. If you rewind T4, be certain to use teflon insulated wire. Take a good look at your low pass filters - count the number of turns on the toroids, re-check the capacitors for the proper value installed in the correct holes, recheck the solder joints in that area. 73, Don Wilhelm - Wake Forest, NC W3FPR home page: http://www.qsl.net/w3fpr/ QRP-L # 485 K2 SN 0020 mailto: w3fpr at arrl.net *** Life is what happens when you're making other plans -- Mike Cross *** ----- Original Message ----- > > Having just finished the first stage of K2 - #2642 and broken my first pile > up with it (OJ0) I am wondering about the output power I am getting. > > On CW I get 12 w on 80 falling to 8w on 10 with 13.5 volts on load ( Cur > 3.0) > I have rewound T2 as per other comments and tried a new binocular core but > the results are about the same. > I now have T2 vertical on the board at right angles to T3 as that gets it > off the board surface. ++++++++++++++++++++ To: elecraft at mailman.qth.net Date: Mon, 10 Jun 2002 21:02:08 -0700 Subject: Re: [Elecraft] Power output From: Gary L Surrency Using the wrong type of core at T1 or T2 can also cause this. Make sure these are FT37-43 grey cores. 73, Gary Surrency AB7MY On Mon, 10 Jun 2002 22:24:50 -0400 "Don Wilhelm" writes: > Bob, > > You should have at least 10 watts of power on 10 meters (assuming > you are > feeding a 50 ohm non-reactive load - like a good dummy load or a > properly > tuned antenna). > > The low pass filters as well as T4 can reduce your power output. > > Check T4 (and T3 too) for the correct number of turns. Gary > Surrency has > said that T4 works much better if the turns are interlaced rather > than just ++++++++++++++++++ Date: Sat, 15 Jun 2002 11:32:53 -0700 From: Phil Wheeler Organization: Outstanding To: Unifiedtx at aol.com Cc: elecraft at mailman.qth.net Subject: Re: [Elecraft] K2 Output on 10 Meters Look here: http://www.qsl.net/kw1nd/k2.htm forgot to include this in my last msg. 73, Phil Unifiedtx at aol.com wrote: >I have heard some say their output exceeds 10 watts on 10 meters. Under what >conditions was this measurement made? >1. What was the voltage showing in the voltage/current display mode? >2. Was the supply voltage increased to 14.4V. to allow for the .6V drop in >the K2? >3. What was the power control set to? (My control will not display higher >than 10 watts on 10 meters.) >4. Was this measured with an accurate wattmeter into a 50 ohm (dummy) load? > >I want to make sure my K2 is ready for prime time to accept the KPA100 and >put out 100 watts on 10 meters. Thanks for any replies. Roy Morris W4WFB >K2 #2225 +++++++++++++++++ Date: Wed, 20 Nov 2002 13:47:27 -0800 From: Wayne Burdick Organization: Elecraft To: Elecraft Subject: [Elecraft] K2 power output tests at low supply voltages I just completed some preliminary tests to see what the K2 could do with really low supply voltages. On 20 meters, both K2s I tested could easily put out 10 watts in CW mode down to as low as 9.5 volts, and 5 watts down to as low as 9.0 volts. In both cases, there was absolutely no hint of frequency shift or other artifacts, and no change in the CW keying waveform (as observed on a scope). I also listened on a separate receiver, and went back and forth between 9 volts and 14 volts while keying at 5 watts. There was no change in quality or signal strength. On the lowest and highest bands I found I had to reduce power slightly below these levels. Based on these tests, here are my (conservative) recommended maximum power settings vs. DC input voltage: DC VOLTAGE POWER OUTPUT ---------- ------------ 9.0 V 2.0 W 9.5 V 5.0 W 10.0 V 7.0 W 10.5 V 10.0 W These figures should be reassuring to anyone who is planning to operate from batteries. The signal will be perfectly stable at 5 watts well below the recommended usable voltage for a depleted 12-V battery. Even a 9.6-volt, 8-cell NiMH battery pack would work in a pinch. (I'd go with C cells, personally.) We'll be adding this table to the K2 performance comparisons page soon. There are some caveats to keep in mind with low voltage operation: - I was using a 95SQ015 at D10 on the RF board (reverse polarity protection diode), rather than the original SB530. The 95SQ015 type drops about 0.2 to 0.3 volts less on transmit. This diode will be included in the rev A to rev B upgrade kit we're working on. - To ensure accuracy when testing at low voltages, the voltage must be measured right at the DC input jack, in transmit mode. Power cables can drop considerable voltage themselves if they're long and/or use small-gauge wire. To minimize this effect, I use at least #18 wire, no longer than 3-5 feet, when possible. - The KBT2 and other 12-V Gel-Cell batteries should not be used below 10 volts for any length of time, as they can become permanently damaged. (The K2 will give you a LO BATT warning as a reminder--see the owner's manual for more details.) Check your supply voltage as needed using the K2's voltage/current display mode (by tapping DISPLAY). - If you want to use the maximum possible power output at a given voltage, rather than the level in the table above, go for it--but listen to the signal on another receiver first to make sure the keying is still crisp and clean. 73, Wayne N6KR ++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'Elecraft'" Subject: RE: [Elecraft] K2 power output tests at low supply voltages Date: Wed, 20 Nov 2002 22:54:09 +0100 I just tested an aircraft emergency locator transmitter battery with indicated voltage of 13-14 Volts (no load) on my K2. A fellow ham here has a large supply as they are routinely replace every year for safety reasons. So now I understand why I got reports of modulation on my 5W CW when the indicated voltage dropped down to 8.5 Volts or so. I guess the low drop 8 Volt regulators get a hard time then..... 73 Sverre LA3ZA > -----Original Message----- > From: elecraft-admin at mailman.qth.net > [mailto:elecraft-admin at mailman.qth.net] On Behalf Of Wayne Burdick. > > On 20 meters, both K2s I tested could easily put out 10 watts > in CW mode down to as low as 9.5 volts, and 5 watts down to > as low as 9.0 volts. In both cases, there was absolutely no > hint of frequency shift or other artifacts, and no change in > the CW keying waveform (as observed on a scope). ++++++++++++++++ Date: Thu, 12 Dec 2002 23:06:59 -0800 From: Wayne Burdick Organization: Elecraft To: TL , Elecraft Subject: [Elecraft] Re: K2 Output power Isaac, Your external meter may not be accurate in the 10-watt range. Most of them are calibrated at 50 or 100 watts and some tend to be inaccurate at the low end due to excessive drop across the detector diodes. But if you feel that you should be able to get power up further, send e-mail to Gary (support at elecraft.com). He'll send you a full list of suggestions. On 10 and 12 meters, check the "Po28" secondary menu entry, which may be artficially limiting max power on these bands. That's its function. Po28 is further described in the "K2 Rev 2 Firmware Manual" (and now in the latest K2 manual, revision D). If you see a drop of as much as 0.9V on TX, it's probably a combination of about 0.5 V across the reverse-polarity diode (SB530) and the rest across your power supply cable leads (half on the hot and half on the ground lead). This is perfectly normal, and is not the limiting factor on power output if your supply is putting out 13.6 V nominally. But you can recover most of this drop, if you want, by doing two things: 1. Use a 95SQ015 diode rather an SB530 (supplied with our "K2ATOBKT" mod kit). 2. Use much heavier power supply wires. As for your 300 mA receive current drain, you can of course reduce this when necessary to about 150-180 mA by following the suggestions in the manual (see the "Advanced Operating Features" section). 73, Wayne N6KR TL wrote: > > Hello all K2 users > Just finished an extensive set of MODS to # 1574 and very happy with results > (AF Pot, all filter Xtals change, ALC, Sidetone, Agc). > After carefully adjusting my K2 "by the book" I find my output power / > current (dummy load) to be as follows: > band power current > 80 10.3w 2.1A > 40 10.0w 2.2A > 20 9 w 2.3A > 15 8.8w 2.4A > 10 8 w 2.6A > > My RX voltage / current reading is 13.6v 0.30 A, on a K2 equipped with > KIO2, KSB2,KNB2 > K160M and a small AMP keying interface. > > I have noticed an 0.6 V- 0.9 V drop on TX when level is set to 6-10w ( band > dependant.). > These power reading , are from my external analog power meter and are always > lower by > 0.2w to 1.5w from K2's internal power meter indication. (worst case 28 > Mhz). +++++++++++++++ Date: Tue, 20 May 2003 19:10:54 +1200 From: Ron W To: Elecraft Reflector Subject: [Elecraft] Fw: Strange loss of output... Hi again, I will be able to answer my own problem it appears...I took the set apart and checked the soldering on the toroids in the 20/30 BP and LP sections (even took them out to check the tinning). No problems there, so I resoldered all connections in the immediate area. Put it all back together. Still the same. ie. only 5w max out on 20m. Remembering past messages about variable trimmers and "seating" them I tried spinning the trimmers a few times, had another go at tuning the filters and it worked. I now have much the same output on all bands. I just have to hope it doesn't change again, but if it does I know where to look. Cheers.....Ron ZL1TW > Hi all, > I wonder if anyone can suggest what might be wrong here.....here is > the scenario: > For a while now the power out on 20m has been low. Today I can max about 35 > watts, so I took the long suffering K2 apart and went through the transmit > alignment again, put it all together. No change. > I then removed the KPA100 completely, powered the set from the old "QRP" > jack and looked again. > I can set the L8 and L9 for max power output on both 20 and 30m as > described. No problem there. I then peak C21 and C 23 for max power . Once > again no problem. > I can up the power to 5 watts and all bands show the same output on the watt > meter. > I set the power level to 10 watts and all bands show 10 watts (near enough) > *EXCEPT* for 20m which still shows 5 watts. I just can't get 20m to give > any output above 5 watts. > I guess a problem like this reeks of dud soldering on a toroid (?) , but > if > 30m ,( which shares the LP and BP filters) is fine , then where? > Having posted this I will go over the connections of the BP and LP > filters, > ....and that means taking off that gosh-awful heatsink panel > > Any ideas appreciated in the meantime. > Cheers......Ron ZL1TW > +++++++++++++++++